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Palacrodon, a near-crown stem reptile, is known from several Triassic sites across the globe, and is easily recognized by its dentition characterized by labiolingually expanded molariform teeth coupled with acrodont tooth implantation. Here we explore the nature of tooth implantation and attachment in specimens of Palacrodon from South Africa and Arizona, U.S.A. using µCT. We note the presence of unusual ridges located underneath the tooth crowns in Palacrodon browni. Such ridges are not present in specimens from Arizona, which warrants the naming of a new species P. parkeri. We conducted a broad survey of internal tooth morphology across extant and extinct pan-reptiles (n = 212), and we conclude that homologous ridges like those we observe in P. browni are not present in any other species of reptile. As such, our ability to determine the function of the ridges is limited, though we hypothesize it is related to tooth attachment via unmineralized soft tissues. [ABSTRACT FROM AUTHOR]

The article focuses on the history of the Catalogue of American Amphibians and Reptiles (CAAR), discussing its beginnings and evolution, including changes in editorial leadership and the expansion of its scope to encompass a broader range of American taxa. It also highlights the contributions of key individuals involved in the CAAR's development and publication.

We provide the first documentation of morphological variation in the lower first molar (m1) of Lemmiscus curtatus from southern Canada. A total of 370 specimens were obtained from owl pellets taken from 4 localities in southern Saskatchewan. The 4 most common morphotypes are, in order of descending relative abundance, molars with 5 closed triangles and a well-developed but widely open sixth triangle, molars with 5 closed triangles and a sixth triangle that is pinched at the confluence of the anterior cap, molars with 5 closed triangles and incipient closure of the sixth triangle from the anterior cap, and specimens with 6 closed triangles. As is true of other modern populations of L. curtatus, the samples from Saskatchewan include no morphotypes with only 4 closed triangles. This collection is notable for the relatively high proportion of specimens with pinched, incipient, or full closure of a sixth triangle on the ml, and it also highlights the complex dynamics of dental evolution in arvicoline rodents. [ABSTRACT FROM AUTHOR]

Uropeltids form a diverse clade of highly derived, fossorial snakes that, because of their phylogenetic position among other alethinophidian lineages, may play a key role in understanding the early evolution of cranial morphology in snakes. We include detailed osteological descriptions of crania and mandibles for eight uropeltid species from three nominal genera (Uropeltis, Rhinophis, and Brachyophidium) and emphasize disarticulated elements and the impact of intraspecific variation on previously proposed morphological characters used for phylogenetic analysis. Preliminary analysis of phylogenetic relationships strongly supports a clade composed exclusively of species of Plectrurus, Uropeltis, and Rhinophis. However, monophyly of each of those genera and Melanophidium is not upheld. There is moderate support that Sri Lankan species (e.g., Rhinophis and Uropeltis melanogaster) are monophyletic with respect to Indian uropeltids. Previously proposed characters that are phylogenetically informative include the shape of the nasals, length of the occipital condyle, level of development of the posteroventral process of the dentary, and participation of the parietal in the optic foramen. Additionally, thirty new features that may be systematically informative are identified and described, but were not verified for their utility. Such verification must await availability of additional disarticulated cranial material from a larger sample of taxa. All characters require further testing through increased focus on sources and patterns of intraspecific variation, inclusion of broader taxonomic samples in comparative studies, and exploration of skeletal development, sexual dimorphism, and biogeographic patterns. Additionally, trends in the relative enlargement of the sensory capsules, reduction in cranial ossification and dentition, fusion of elements, and the appearance of novel morphological conditions, such as the structure and location of the suspensorium, may be related to fossoriality and miniaturization in some uropeltid taxa, and may complicate analysis of relationships within Uropeltidae and among alethinophidian snakes. [ABSTRACT FROM AUTHOR]

Abstract: The North American Pleistocene Herpetofaunal Stability Hypothesis was established in the 1980s based on summary reviews of primary descriptive paleoherpetological literature. The hypothesis posits that North American herpetofaunas essentially were taxonomically and geographically stable throughout the Quaternary. Modern biogeographic distribution of species served as an important criterion for primary identification of the majority of fossil herpetofaunal specimens, rendering the Herpetofaunal Stability Hypothesis circular. Apomorphy-based identifications are an important and well-established alternative to the traditional approach, but are used only rarely within the Quaternary paleontology community. Preliminary applications of the apomorphy-based approach reveal that species-level resolution often is not possible for herpetofaunal remains. Lack of species-level resolution may be a consequence of poor documentation of evolutionary morphology for most herpetofaunal species lineages. Development of adequate skeletal collections and the search for apomorphies in the anatomical systems typically preserved in Quaternary deposits will yield meaningful insights into evolutionary morphology, an enhanced appreciation of Quaternary faunal dynamics, and a greater concordance with modern neontological approaches. Maintenance of traditional methods of identification will yield a false perception of clarity, erroneous interpretations of Quaternary faunal dynamics, and may perpetuate misleading data in Quaternary paleontology as well as other fields that rely on those data. [Copyright &y& Elsevier]

Anniella is a clade within Anguidae including small-bodied serpentiform lizards, previously hypothesized to be miniaturized relative to other parts of Anguidae. Ancestrally, Anguidae displays an extensive armor of dermal ossifications, but the presence or absence of osteoderms in Anniella was a source of some confusion in the past. We confirm that Anniella possesses osteoderms in the dermis deep to nearly every epidermal body scale, as well as remnant ossifications deep to the head scales. The body osteoderms display three basic components: an anterior plate bearing apparent growth ridges, a usually constricted neck portion with a distinct microstructure, and a branching portion divided into a variable number of processes. Under high magnification, collagen bundles similar to those on other lizard osteoderms are visible. The osteoderms of Anniella are reduced in their ossification relative to those of other Anguidae; they are thinner, occupy only the middle regions of the dermal scale component, and their posterior portions appear only as a series of fingerlike processes. Reduction in the osteoderms of Anniella constrasts with reinforced solidity of many of the skull elements, supporting the idea that modularity was involved in the evolution of miniaturization in this clade. [ABSTRACT FROM AUTHOR]

The mechanisms that enable the heart to rapidly increase ATP supply in line with increased demand have not been fully elucidated. Here we used an adenoviral system to express the photoproteins luciferase and aequorin, targeted to the mitochondria or cytosol of adult cardiomyocytes, to investigate the interrelationship between ATP and Ca2+ in these compartments. In neither compartment were changes in free [ATP] observed upon increased workload (addition of isoproterenol) in myocytes that were already beating. However, when myocytes were stimulated to beat rapidly from rest, in the presence of isoproterenol, a significant but transient drop in mitochondrial [AlP] ([ATP]m) occurred (on average to 10% of the initial signal). Corresponding changes in cytosolic [ATP] ([ATP]m) were much smaller (<5%), indicating that [ATP]c was effectively buffered in this compartment. Although mitochondrial [Ca2+] ([Ca2+]m) is an important regulator of respiratory chain activity and ATP production in other cells, the kinetics of mitochondrial Ca2+ transport are controversial. Parallel experiments in cells expressing mitochondrial aequorin showed that the drop in [ATP]m occurred over the same time scale as average [Ca2+]m was increasing. Conversely, in the absence or presence of isoproterenol, clear beat-to-beat peaks in [Ca2+]m were observed at 0.9 or 1.3 μM, respectively, concentrations similar to those observed in the cytosol. These results suggest that mitochondrial Ca2+ transients occur during the contractile cycle and are translated into a time-averaged increase in mitochondrial ATP production that keeps pace with increased cytosolic demand. [ABSTRACT FROM AUTHOR]

Mid-Pleistocene vertebrates in North America are scarce but important for recognizing the ecological effects of climatic change in the absence of humans. We report on a uniquely rich mid-Pleistocene vertebrate sequence from Porcupine Cave, Colorado, which records at least 127 species and the earliest appearances of 30 mammals and birds. By analyzing >20,000 mammal fossils in relation to modern species and independent climatic proxies, we determined how mammal communities reacted to presumed glacial-interglacial transitions between 1,000,000 and 600,000 years ago. We conclude that climatic warming primarily affected mammals of lower trophic and size categories, in contrast to documented human impacts on higher trophic and size categories historically. Despite changes in species composition and minor changes in small-mammal species richness evident at times of climatic change, overall structural stability of mammal communities persisted >600,000 years before human impacts. [ABSTRACT FROM AUTHOR]

Presents a study which provided a phylogenetic perspective on the behavior of ferrets combined through the use of paleontological data. Geographic and chronological setting; Materials and methods; Results; Discussion of the results.

High-resolution computed tomography (HRCT) has become a widely used tool for studying the inner ear morphology of vertebrates. Amphisbaenians are one of the most specialized groups of fossorial reptiles but are poorly understood relative to other squamate reptile. In this paper we survey the anatomy of the inner and middle ear of these fossorial reptiles using HRCT models and we describe qualitatively and quantitatively (using 3D morphometrics) the anatomy of the inner ear. Amphisbaenians are diverse in skull anatomy, especially in the configuration of the snout, which correlates with digging modes. We demonstrate that the ear also exhibits a diversity of configurations, which are independent of phylogenetic relationships. Results from morphological analyses also allow us to describe 11 new potentially informative phylogenetic characters including some that help to diagnose amphisbaenians, such as: 1) the globular vestibule, ii) semicircular canals arranged in a circular trajectory, and iii) an extensive area of interaction between the columella footplate and the lagenar recess. Among extant amphisbaenians, Rhineura floridana has the most unusual inner ear configuration, including a horizontal semicircular canal that is in the same orientation as the inclined snout. The new morphological information helps us to better understand the morphology of headfirst-burrowing fossorial reptiles and contributes new data for resolution of phylogenetic relationships among amphisbaenians. [ABSTRACT FROM AUTHOR]

The Beringian Land Bridge is a well-documented dispersal corridor between the Eurasian continent and North America. Episodic sub-aerial exposure of the land bridge during the Late Cenozoic resulted from climatic oscillations and concomitant lowering of sea level. For much of the Pleistocene, dispersal was predominantly west-to-east (e.g., from Eurasia to North America), but a new discovery of the North American rodent Phenacomys from deeply buried sediments in The Netherlands documents an Early Pleistocene east-to-west invasion. The discovery reinforces earlier suggestive hints of an integrated Holarctic mammal fauna in the Early Pleistocene and provides a unique opportunity to establish a direct correlation of the classic mammal zonations of Europe and North America. Phenacomys is traditionally conceptualized as an endemic North American radiation of voles, and all extant taxa are exclusively North American. The first European remains of Phenacomys were recovered as part of the Zuurland Drilling Project from earliest Pleistocene (ca, 2.3–2.1 Ma) strata. The specimens were found in stratigraphic association with species that are well-known from more southern European assemblages of Early Pleistocene age, but also with contemporaneous taxa traditionally associated with more northern latitudes. The recognition of Phenacomys within the Zuurland assemblage demonstrates that the Bering Land Bridge served as a corridor for dispersal of mammal species during the earliest Pleistocene, and served as a physiographic mechanism for the integration of a circumpolar biogeographic province at that time. [ABSTRACT FROM AUTHOR]

The article cites the practicalities of measuring and interpreting field metabolic rate in dogs. Separation of energy expenditure of a dog for work from its daily energy expenditure when not working is considered necessary for the measurements of field metabolic rate using the doubly-labeled water technique to be correctly interpreted and used to determine energy requirements of working dogs. Total energy expenditure can be separated into components for maintenance, standing and other activities. Time- or energy-budget analysis is also said to be necessary to estimate average daily energy expenditure.

Records of turtle remains from Pleistocene deposits in western North America are scarce, suggesting that turtles were uncommon in western landscapes throughout the Pleistocene. However, low numbers of fossils do not necessarily correlate with rarity in the past because taphonomic bias can have a marked impact on shaping what is preserved in the fossil record. We compiled minimum species richness data for 8 geographic regions by depositional setting (caves and open-air sites) and used a 2-factor analysis of variance to examine the effects of geographic region and depositional setting on turtle species richness. We did not find a statistically significant effect of depositional setting on turtle richness, suggesting that the paucity of turtles in the Pleistocene of western North America does not result from that particular form of taphonomic bias. Also, we found a strong regional variation in turtle richness that was dependent on time interval, suggesting a potential shift in regional patterns of richness since the Pleistocene. [ABSTRACT FROM AUTHOR]

Background Previous studies, including those employing diffusion tensor imaging ( DTI), have revealed significant disturbances in the white matter of individuals with fetal alcohol spectrum disorders ( FASD). Both macrostructural and microstructural abnormalities have been observed across levels of FASD severity. Emerging evidence suggests that these white matter abnormalities are associated with functional deficits. This study used resting-state functional MRI (f MRI) to evaluate the status of network functional connectivity in children with FASD compared with control subjects. Methods Participants included 24 children with FASD, ages 10 to 17, and 31 matched controls. Neurocognitive tests were administered including Wechsler Intelligence Scales, California Verbal Learning Test ( CVLT), and Behavior Rating Inventory of Executive Functioning. High-resolution anatomical MRI data and 6-minute resting-state fMRI data were collected. The resting-state f MRI data were subjected to a graph theory analysis, and 4 global measures of cortical network connectivity were computed: characteristic path length, mean clustering coefficient, local efficiency, and global efficiency. Results Results revealed significantly altered network connectivity in those with FASD. The characteristic path length was 3.1% higher ( p = 0.04, Cohen's d = 0.47), and global efficiency was 1.9% lower ( p = 0.04, d = 0.63) in children with FASD compared with controls, suggesting decreased network capacity that may have implications for integrative cognitive functioning. Global efficiency was significantly positively correlated with cortical thickness in frontal ( r = 0.38, p = 0.005), temporal ( r = 0.28, p = 0.043), and parietal ( r = 0.36, p = 0.008) regions. No relationship between facial dysmorphology and functional connectivity was observed. Exploratory correlations suggested that global efficiency and characteristic path length are associated with capacity for immediate verbal memory on the CVLT ( r = 0.41, p = 0.05 and r = 0.41, p = 0.01, respectively) among those with FASD. Conclusions Resting-state functional connectivity measures provide new insight into the integrity of brain networks in clinical populations such as FASD. Results demonstrate that children with FASD have alterations in core components of network function and that these aspects of brain integrity are related to measures of structure and cognitive functioning. [ABSTRACT FROM AUTHOR]

The article discusses the best practices for justifying fossils utilized for the temporal calibration of molecular phylogenies. It examines the challenges connected with using paleontological data. It states that incorrect phylogenetic placement of fossil calibrations can bring large errors into divergence date calculations. It adds that even when relatively complete specimens are available, the phylogenetic position of a fossil taxon can be unstable.

Uropeltid snakes are among the most poorly understood clades within Alethinophidia. Their small size, limited geographic distribution, high incidence of endemism, and fossorial behaviour all contribute to the general paucity of systematic collections of these snakes, especially of adequate skeletal preparations, in most museum collections. Their hypothesized position within the higher-order phylogeny of alethinophidian snakes calls attention to the need for additional morphological work on the group. Hypotheses of uropeltid phylogenetic relationships based on morphological analyses are few, and continue to be hampered by limited taxon-sampling and character matrices that rely predominantly on features that are visible on articulated skulls. We utilized high-resolution X-ray computed tomography (HRCT) to investigate the cranial osteology of Plectrurus aureus Beddome, 1880, a species for which no osteological data were previously available. We provide a detailed description of the skull and mandible, and comment on morphological characters and potential phylogenetic relationships. Clarity in character descriptions is of paramount importance, and additional morphological characters are desirable. HRCT provides a nondestructive way to identify new systematically informative morphological characters from digitally disarticulated specimens. The small size of many uropeltid species, including P. aureus, will help to frame a greater appreciation of the limitations of traditional HRCT protocols for revealing detailed anatomical features of small vertebrates. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160, 118–138. [ABSTRACT FROM AUTHOR]

In 2008 a rich accumulation of vertebrate bones and teeth was discovered in a small tributary drainage to Big Cypress Creek near the town of Hockley in Harris County, Texas. The fossils were recovered from sandy sediments of fluvial origin, interspersed with contemporaneous spring boil deposits, attributed to the Deweyville Formation and the recovered remains consist entirely of disarticulated and dissociated skeletal elements and teeth. Distinct stratigraphic horizons are limited in extent in the fossiliferous sections along the drainage, and the fossils are generally concentrated in close association with gravel lag deposits. Two radiocarbon dates on wood suggest that the fauna may have accumulated about 24,000 years ago but presence of spring deposits, association with lag deposits, and the aerial extent (approximately 125 m of exposed section along the length of the tributary) could indicate significant time averaging during the Rancholabrean (Bison occurs in the fauna). The unique faunal character of the site is emphasized by a single tooth of Mixotoxodon , a notoungulate mammal, that provides the first evidence of this taxon from the United States. The fauna is dominantly composed of herbivorous megafauna with two proboscideans (Mammuthus and Cuvieronius). Mammut americanum has not yet been found in the fauna. Isotopic analyses of the proboscideans and some of the other megafauna suggest that an open environment with scattered woodland habitat existed in southeastern Texas at the end of the last glacial period. [ABSTRACT FROM AUTHOR]

δ 13 C records from vertebrate teeth offer an opportunity to gain insight into changes in past vegetation. Increasingly, teeth from small mammals are used for such purposes, but because their teeth grow rapidly, seasonal changes in vegetation are potentially a large source of variability in their carbon isotope composition, complicating interpretations of isotope data. To investigate the influence of seasonality on the stable isotope composition of fossil teeth, we constructed a Monte-Carlo-based model to simulate the effects of changes in the seasonal pattern of diet in leporid lagomorphs (rabbits and hares) on the distribution of δ 13 C values in random populations of leporid teeth from the Edwards Plateau in central Texas. Changes in mean-state, seasonal vegetation range, and relative season length manifest themselves in predictable ways through changes in the median, standard deviation, and skewness of simulated tooth δ 13 C populations, provided sufficient numbers of teeth are analyzed. This Monte Carlo model was applied to the interpretation of a 20,000 year record of leporid tooth δ 13 C values from Hall's Cave on the Edwards Plateau in central Texas. Populations of teeth from different climate intervals (e.g., the late Glacial, Younger Dryas, and the Holocene) display changes in tooth δ 13 C distributions that may reflect changes in seasonal vegetation. The inferred changes in seasonality of vegetation based upon our modeling are consistent with hypothesized climatic changes. These results indicate that small mammal teeth can potentially provide unique insights into climate and vegetation on seasonal and longer timescales that complement other approaches, but should be interpreted with a careful consideration of local conditions, taxon ecology and physiology, and the dominant timescales of isotope variability in a rigorous statistical framework. [ABSTRACT FROM AUTHOR]

MRI studies, including recent diffusion tensor imaging (DTI) studies, have shown corpus callosum abnormalities in children prenatally exposed to alcohol, especially in the posterior regions. These abnormalities appear across the range of fetal alcohol spectrum disorders (FASD). Several studies have demonstrated cognitive correlates of callosal abnormalities in FASD including deficits in visual-motor skill, verbal learning, and executive functioning. The goal of this study was to determine whether inter-hemispheric structural connectivity abnormalities in FASD are associated with disrupted inter-hemispheric functional connectivity and disrupted cognition. Twenty-one children with FASD and 23 matched controls underwent a 6-minute resting-state functional MRI scan as well as anatomical imaging and DTI. Using a semi-automated method, we parsed the corpus callosum and delineated 7 inter-hemispheric white matter tracts with DTI tractography. Cortical regions of interest (ROIs) at the distal ends of these tracts were identified. Right-left correlations in resting fMRI signal were computed for these sets of ROIs, and group comparisons were made. Correlations with facial dysmorphology, cognition, and DTI measures were computed. A significant group difference in inter-hemispheric functional connectivity was seen in a posterior set of ROIs, the para-central region. Children with FASD had functional connectivity that was 12% lower than in controls in this region. Subgroup analyses were not possible owing to small sample size, but the data suggest that there were effects across the FASD spectrum. No significant association with facial dysmorphology was found. Para-central functional connectivity was significantly correlated with DTI mean diffusivity, a measure of microstructural integrity, in posterior callosal tracts in controls but not in FASD. Significant correlations were seen between these structural and functional measures, and Wechsler perceptual reasoning ability. Inter-hemispheric functional connectivity disturbances were observed in children with FASD relative to controls. The disruption was measured in medial parietal regions (para-central) that are connected by posterior callosal fiber projections. We have previously shown microstructural abnormalities in these same posterior callosal regions, and the current study suggests a possible relationship between the two. These measures have clinical relevance as they are associated with cognitive functioning. [ABSTRACT FROM AUTHOR]

Abstract: Major depressive disorder (MDD) begins frequently in adolescence and is associated with severe outcomes, but the developmental neurobiology of MDD is not well understood. Research in adults has implicated fronto-limbic neural networks in the pathophysiology of MDD, particularly in relation to the subgenual anterior cingulate cortex (ACC). Developmental changes in brain networks during adolescence highlight the need to examine MDD-related circuitry in teens separately from adults. Using resting state functional magnetic resonance imaging (fMRI), this study examined functional connectivity in adolescents with MDD (n =12) and healthy adolescents (n =14). Seed-based connectivity analysis revealed that adolescents with MDD have decreased functional connectivity in a subgenual ACC-based neural network that includes the supragenual ACC (BA 32), the right medial frontal cortex (BA 10), the left inferior (BA 47) and superior frontal cortex (BA 22), superior temporal gyrus (BA 22), and the insular cortex (BA 13). These preliminary data suggest that MDD in adolescence is associated with abnormal connectivity within neural circuits that mediate emotion processing. Future research in larger, un-medicated samples will be necessary to confirm this finding. We conclude that hypothesis-driven, seed-based analyses of resting state fMRI data hold promise for advancing our current understanding of abnormal development of neural circuitry in adolescents with MDD. [Copyright &y& Elsevier]